The low-rank approximation of a (2nd-order) tensor \(\mathbf {Q} \in \mathbb {R}^{M \times N}\)  can be obtained by the multiplication of two tensors \(\mathbf {H} \in \mathbb {R}^{M \times K}\)  and \(\mathbf {V} \in \mathbb {R}^{K \times N}\)  [1]}:
\(\mathbf {Q} \approx \mathbf {H} \times \mathbf {V}. \) 
